This K01 Mentored Research Scientist Development Award will provide advanced training for the candidate to become an independent investigator focusing on HIV prevention strategies that link epidemiology, behavioral science, and economic development. The long-term goal of the investigator is to develop, implement, and evaluate innovative and multidisciplinary interventions to reduce the incidence of HIV infection among women and girls in the developing world. The proposed scope of work includes both training and research components that capitalize on the rich interdisciplinary research environment at the University of California, Berkeley as well as the institutions of the candidate's advisory committee. The training component forms the foundation of the proposal and includes two senior mentors, a panel of advisors with complementary expertise, didactic education, skill development, and mentored research such that at the completion of the award the candidate will be well-positioned for an independent research career. The training plan has been developed in parallel with the mentored research plan such that when new education and skills are obtained they can be immediately applied to the relevant aspects of the research program. Four training objectives will be accomplished during the course of this award: (1) obtain education in the responsible conduct of research, economics, and international development policy; (2) obtain practical skills in agricultural and resource economics, intervention development, and the conduct and analysis of experimental epidemiological studies; (3) complete a mentored research program to design and pilot an HIV prevention intervention; and (4) become an independent investigator through building the publication record, mentoring by subject matter experts, and generating pilot data for a future proposal. The goal of the research component is to examine how the economic context shapes women's vulnerability to HIV infection in rural Tanzania and to pilot an intervention to economically empower women farmers and reduce HIV infection. The promotion of women's economic empowerment is increasingly viewed as a promising approach to HIV prevention in Sub-Saharan Africa as the lack of access to and control over economic resources heightens susceptibility to HIV infection. This proposal takes an innovative approach to HIV prevention by focusing on agriculture, which is inextricably linked to poverty and food security in the developing world. However, few interventions have systematically integrated agricultural livelihoods, food security, and HIV prevention. The research aims are to: (1) investigate the potential for a sustainable agriculture-based livelihood intervention to reduce the risk of HIV infection among women farmers in Tanzania; (2) determine the effect of household income, food insecurity, and land ownership on sexual risk-taking among female-headed farming households in Tanzania; and (3) conduct a pilot study of a sustainable agriculture- based livelihood intervention for women farmers in Tanzania to improve household income and food security and reduce sexual risk-taking. This study will provide quantitative and qualitative evidence to determine whether a future trial is merited for the intervention. There is a clear need for empirical evidence about the effects of economic insecurity on HIV vulnerability. In addition, the development of multi-sectoral responses to prevention that can address the entwined economic, social, and contextual risks with which African women contend is imperative. This proposal has been designed to address both of these needs and the results will have important implications for future responses to the HIV pandemic.